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United States Patent |
5,585,430
|
Patel
,   et al.
|
December 17, 1996
|
Pintle wire
Abstract
A pintle wire comprises a polymer material containing a lubricant material
of schistose nature. The polymer material comprises polyamide, polyester,
copolyester, polyetheretherketone or polyphenylene sulphide. The schistose
lubricant comprise graphite, molybdenum sulphide, cobalt sulphide, clay or
silicate.
Inventors:
|
Patel; Sanjay (Summerville, SC);
Crook; Robert L. (Wilson, NC)
|
Assignee:
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Scapa Group PLC (Lancashire, GB)
|
Appl. No.:
|
523863 |
Filed:
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September 6, 1995 |
Current U.S. Class: |
524/406; 524/418; 524/419; 524/435; 524/445; 524/447; 524/495; 524/496 |
Intern'l Class: |
C08K 003/10 |
Field of Search: |
524/495,496,406,418,419,435,445,447
|
References Cited
U.S. Patent Documents
4007303 | Feb., 1977 | Schuster et al. | 427/296.
|
4607073 | Aug., 1986 | Sakashita et al. | 524/404.
|
Primary Examiner: Cain; Edward J.
Attorney, Agent or Firm: Keck, Mahin & Cate
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part application of Ser. No.
08/301,983, filed Sep. 6, 1994, now abandoned.
Claims
We claim:
1. A polymeric pintle wire formed by extrusion and containing a lubricant
material of schistose nature, wherein the lubricant material has a BET
value of at least 12 m.sup.2 /g.
2. A pintle wire as claimed in claim 1, wherein the lubricant material
comprises at least one member selected from the group consisting of:
graphite, molybdenum sulphide, cobalt sulphide, clay and silicate.
3. A pintle wire as claimed in claim 1, wherein the lubricant material
comprises graphite.
4. A pintle wire as claimed in claim 1, wherein the polymer comprises at
least one member selected from the group consisting of: polyamide,
polyester, copolyester, polyolefin, polyetheretherketone and polyphenylene
sulphide.
5. A pintle wire as claimed in claim 1, wherein the wire comprises no more
than 3% of lubricant material by weight of the polymer.
6. A pintle wire as claimed in claim 5, wherein the wire comprises no more
than 1% of lubricant material by weight of the polymer.
7. A pintle wire as claimed in claim 1, wherein the lubricant material has
a BET value in the range from 16 to 22 m.sup.2 /g.
Description
FIELD OF THE INVENTION
The present invention relates to a pintle wire, particularly but not
exclusively for use in joining the ends of industrial fabrics, such as
papermachine clothing, for example press felts and dryer fabrics.
BACKGROUND OF THE INVENTION
It is known to join together two ends of a fabric using a pintle wire so as
to provide an endless belt. Each end of the fabric is provided with
outwardly extending loops, the two sets of loops being interdigitable and
capable of union by a pintle wire. As these joints can be up to 10 meter
in length it will be appreciated that it is difficult to pass the pintle
wire down the length of the tunnel defined by the interdigitated loops due
to friction between the wire and the loops. Furthermore there may be
significant yarn to yarn abrasion of the pintle wire and loops whilst the
fabric is running on the papermachine.
It is known to coat pintle wires with a resin coating in order to reduce
abrasion of the pintle wire. However, the coating undesirably increases
the rigidity of the wire. It is also difficult to obtain a uniform coating
on the pintle wire and to obtain good adhesion of the resin to the wire.
SUMMARY OF THE INVENTION
The present invention seeks to provide an alternative solution to the
aforementioned problems.
According to the present invention there is provided a pintle wire
comprising polymer formed by extrusion and containing a lubricant material
of schistose nature.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Schistose materials are materials, such as minerals, which comprise a
network of weakly bonded infinite molecular layers. Examples of such
materials include graphite, molybdenum sulphide, cobalt sulphide, clays
and silicates such as talc or vermiculite. Graphite is preferred. This is
because graphite offers superior yarn to yarn abrasion resistance. Tests
have shown that graphite is significantly superior to molybdenum sulphide
in this respect. The specific surface area (BET value) of the schistose
material is preferably at least 12 m.sup.2 /g and is most preferably 16 to
2 m.sup.2 /g. Materials having such a high BET value provide a greater
polymer-graphite contact area, thus increasing the elongation at break of
the pintle wire. Small surface area particles behave as fillers and their
random orientation makes the pintle wire more brittle. The large surface
area particles, however, are not so brittle in that the particles become
orientated in the length direction of the pintle wire.
The polymer may comprise any of the following: polyamides such as Nylon,
for example type PA6, PA6.6, PA6.10, PA6.12, polyesters, copolyesters,
polyetheretherketone or polyphenylene sulphide or polyolefins.
Preferably no more than 3% of schistose lubricant material and more
preferably no more than 1% of schistose lubricant by weight of the polymer
is added to the polymer.
The wires of the invention may be formed from the polymer mixture by
standard extruding techniques.
The impregnated pintle wires of the invention are more easily inserted into
the tunnel of interdigitated loops because of reduced drag and friction as
the wire passes through the loops. The wires of the invention also exhibit
reduced distortion and lead to reduced distortion of the interdigitated
loops.
The impregnated wires preferably provide a visual contrast with the belt,
for example graphite impregnated wires are black whereas press felts are
usually brown or white. The visual contrast makes it easier to insert the
wire in the tunnel of loops.
A further advantage is that yarn to yarn abrasion of the wire and loops is
less than that for conventional pintle wares. For example, at a speed of
32 cm/s a pintle wire comprising Nylon 6.10 impregnated with about 1 wt %
graphite gave a fibre-fibre friction coefficient of 0.09 compared with
0.11 for neat Nylon 6.10 and 0.12 for Nylon 6.10 impregnated with about 1
wt % Teflon or molybdenum sulphide.
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